[MD] Change appearance of incognito NTP to MD spec.

chrome/browser/resources/ntp4/new_tab.js

Index: chrome/browser/resources/ntp4/new_tab.js
diff --git a/chrome/browser/resources/ntp4/new_tab.js b/chrome/browser/resources/ntp4/new_tab.js
index cb0c42dc9d0fcaf35773a4ffb6c77324a222436e..a1cef2c8ef2b22d3cb6a2c445be01b7ae44b570b 100644
--- a/chrome/browser/resources/ntp4/new_tab.js
+++ b/chrome/browser/resources/ntp4/new_tab.js
@@ -334,7 +334,7 @@ cr.define('ntp', function() {
   /**
    * Called when the theme has changed.

[Dan Beam, 2015/11/20 00:48:45]

@param {Type=} opt_themeData Description.

[Evan Stade, 2015/11/20 22:05:17]

Done.

    */
-  function themeChanged() {
+  function themeChanged(opt_themeData) {
     $('themecss').href = 'chrome://theme/css/new_tab_theme.css?' + Date.now();
   }